Hood

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  • Country
  • Volcanic Region
  • Primary Volcano Type
  • Last Known Eruption
  • 45.374°N
  • 121.695°W

  • 3426 m
    11237 ft

  • 322010
  • Latitude
  • Longitude

  • Summit
    Elevation

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    Number

Most Recent Weekly Report: 26 June-2 July 2002


CVO reported that the strongest earthquake in the Mount Hood area in decades occurred on 29 June at 0736. The widely felt M 4.5 event was located ~4.5 km S of the summit at a depth of 6 km. Hundreds of aftershocks followed, including two greater than M 3. Typically, several earthquake swarms occur each year at Mount Hood.

Sources: US Geological Survey Cascades Volcano Observatory (CVO), Associated Press


Most Recent Bulletin Report: July 2002 (BGVN 27:07)


Strongest earthquake in decades registered on 29 June 2002 (M 4.5); aftershocks

The strongest earthquake in the Mount Hood area in decades occurred on 29 June 2002 at 0736, according to the USGS Cascades Volcano Observatory (CVO). The widely felt M 4.5 event was located ~4.5 km S of the summit (figure 3) at a depth of 6 km. Hundreds of aftershocks followed, including two greater than M 3. Typically, several earthquake swarms occur each year at Mount Hood.

Figure 3. A map of all earthquakes (M 1.0) that occurred at Hood from the start of 2001 to 29 June 2002. The area shown details a few kilometers around the M 4.5 event on 29 June 2002. Courtesy PNSN.

Information Contacts: Cascades Volcano Observatory (CVO), United States Geological Survey (USGS), 5400 MacArthur Blvd., Vancouver, WA 98661, USA (URL: http://vulcan.wr.usgs.gov/); Pacific Northwest Seismograph Network (PNSN), University of Washington, Department of Earth and Space Sciences, Box 351310, Seattle, WA 98195-1310, USA (URL: http://www.ess.washington.edu/SEIS/PNSN/).

Index of Weekly Reports


2002: June
2001: January | September

Weekly Reports


26 June-2 July 2002

CVO reported that the strongest earthquake in the Mount Hood area in decades occurred on 29 June at 0736. The widely felt M 4.5 event was located ~4.5 km S of the summit at a depth of 6 km. Hundreds of aftershocks followed, including two greater than M 3. Typically, several earthquake swarms occur each year at Mount Hood.

Sources: US Geological Survey Cascades Volcano Observatory (CVO); Associated Press


12 September-18 September 2001

The USGS Cascades Volcano Observatory reported that a minor earthquake swarm occurred at Mount Hood from 9 September until at least 14 September. About 25 events were detected, with a maximum magnitude of 2.9. The epicenters of the earthquakes were ~8 km SSW of the volcano's summit at depths of 1-7 km. These types of swarms occur once or twice per year at Mount Hood.

Source: US Geological Survey Cascades Volcano Observatory (CVO)


17 January-23 January 2001

The Cascades Volcano Observatory (CVO) reported that during 10-20 January a swarm of 13 earthquakes with magnitudes ranging from 0.2-2.0 occurred in an area about 4-8 km SSE of the summit at a depth of 4-7 km. This activity is not abnormal; Mount Hood averages one to two small swarms a year, with the last swarm occurring in May 2000. The current swarm consisted of fewer and smaller events than is typical, but it may not have yet ended.

Sources: US Geological Survey Cascades Volcano Observatory (CVO); Associated Press


Index of Bulletin Reports


Reports are organized chronologically and indexed below by Month/Year (Publication Volume:Number), and include a one-line summary. Click on the index link or scroll down to read the reports.

07/1980 (SEAN 05:07) Earthquake swarm

01/1999 (BGVN 24:01) Mid-January swarms of tectonic earthquakes

06/2001 (BGVN 26:06) Late-1999 mass wasting; January 2001 earthquake swarm

07/2002 (BGVN 27:07) Strongest earthquake in decades registered on 29 June 2002 (M 4.5); aftershocks




Bulletin Reports

All information contained in these reports is preliminary and subject to change.


07/1980 (SEAN 05:07) Earthquake swarm

[Seismic data in the following report have been extensively modified using Rite and Iyer (1981).] A series of earthquakes in the vicinity of Mt. Hood, about 100 km SSE of Mt. St. Helens, began with a M [2.8] shock on 6 July at 1817. [Within 30 minutes, 7 events of M 1.6-2.8 occurred in the vicinity of the first shock. Depths were tightly clustered at 4-7 km.]

[Activity remained anomalously high for about 48 hours after the initial shock, with 40 events recorded on 3-9 stations in the first 24 hours (figure 1). Epicenters were generally on the S flank (figure 2).] A M [2.44] earthquake at 0259 and a M [2.25] event at 1315 were centered [near the summit] at [5.9 and 5.3] km depth. [Between 6-16 July, 143 small events were recorded on a single station (VHE) about 5 km SE of the summit. About 50 were correlated with nearby stump blasting, but the other 90 appeared to be swarm events, most with coda magnitudes less than 0.5.]... The swarm's total seismic energy release [was about 8 x 1015 ergs]....

Figure 1. Histogram of seismic activity at Mt. Hood, 6-20 July 1980, after Rite and Iyer (1981).
Figure 2. Epicenters of most of the July 1980 events at Mt. Hood. Sizes of crosses are proportional to event magnitudes. After Rite and Iyer (1981).

The USGS issued a hazard watch formally notifying government officials. On 11 July, the USGS and the University of Washington installed three portable seismographs on Mt. Hood. No harmonic tremor has been recorded, and no new surface activity has been observed. Gas analyses made from aircraft on 11 July showed no increase in atmospheric SO2 or CO2 above normal levels.

Because no additional seismicity and no new eruptive activity have occurred at Mt. Hood, the USGS ended the hazard watch on 5 August.

References. Rite, A., and Iyer, H.M., 1981, July 1980 Mt. Hood earthquake swarm: USGS Open File Report 81-48, 22 p.

Information Contacts: R. Decker, R. Tilling, and C. Zablocki, USGS; S. Malone, R. Crosson, and E. Endo, Univ. of Washington.
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01/1999 (BGVN 24:01) Mid-January swarms of tectonic earthquakes

An earthquake swarm occurred near Mount Hood in northern Oregon beginning on 11 January. More than two dozen earthquakes were produced that day, the largest of which were M 3.2 (at 1404) and M 3.0 (at 0854). Following a pause during 12-13 January, a M 3.2 earthquake at 0356 and a M 3.0 earthquake at 0813 occurred on 14 January. The largest earthquakes were felt at Timberline, Brightwood, Parkdale, and Mount Hood Meadows. By noon on 14 January the Cascades Volcano Observatory had detected 66 earthquakes, 33 of them large enough to be well-located.

All of the earthquakes in the recent swarms had characteristics similar to tectonic earthquakes rather than volcanic earthquakes (indicative of magma movement). They most likely resulted from regional tectonic stresses, although they may have also been caused by deep-seated changes in the volcano's plumbing system. Additional and significantly different geological and geophysical indicators would be expected before any future eruptive activity. Scientists will continue to monitor the situation closely. They may add additional instrumentation to the monitoring network to learn more about earthquakes in this region.

Since 1990 Hood has produced about fifteen earthquake swarms similar to the recent one. These swarms have lasted from a few hours to several days and have generally produced maximum magnitudes between 1.6 and 3.5. Many earthquakes have been well-located, and are generally clustered 4-7 km S of the volcano's summit. Seismic data of lower quality suggest that swarms also occurred in the 1970s and 1980s. The largest recorded earthquake at Mount Hood was a M 4.0 in December 1974.

Information Contacts: Cascades Volcano Observatory, U.S. Geological Survey, 5400 MacArthur Blvd., Vancouver, WA 98661 USA (URL: http://vulcan.wr.usgs.gov/); Geophysics Program, University of Washington, Seattle, WA 98195 USA (URL: http://www.geophys.washington.edu/).
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06/2001 (BGVN 26:06) Late-1999 mass wasting; January 2001 earthquake swarm

After the earthquake swarms in January 1999 (BGVN 24:01), two reports of anomalous activity at Hood were received; in September and October of 2000 landslides and debris flows traveled down the flanks of the volcano, and in January 2001 small earthquake swarms occurred.

The Cascades Volcano Observatory (CVO) reported that intense rainfall during 30 September to 1 October 2000 triggered a series of landslides and debris flows in several of Hood's drainages. The largest flows occurred in White River Valley on the S flank and Newton Creek Valley on the E flank. Both streams were diverted from their channels and severely damaged two sections of Oregon Highway 35; one section is an important link between I-84 and US 26, and the other is a recreational highway that provides access to Mount Hood Meadows Ski Area. The landslides and debris flows caused more than $1 million in damage. The Oregon Department of Transportation reopened the highway on 27 October.

According to CVO, a small earthquake swarm occurred at Hood during 10-19 January 2001. During this period a swarm of 13 earthquakes, with magnitudes ranging from 0.2-2.0, occurred in an area ~4-8 km SSE of the summit at a depth of 4-7 km. This area is frequently a source of earthquake swarms, but this swarm consisted of fewer and smaller events than is typical. The last similar type of swarm occurred in May 2000. On average, 1-2 swarms of small earthquakes occur at Hood each year.

Information Contacts: Cascades Volcano Observatory, U.S. Geological Survey, 5400 MacArthur Blvd., Vancouver, WA 98661 USA (URL: http://vulcan.wr.usgs.gov/).
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07/2002 (BGVN 27:07) Strongest earthquake in decades registered on 29 June 2002 (M 4.5); aftershocks

The strongest earthquake in the Mount Hood area in decades occurred on 29 June 2002 at 0736, according to the USGS Cascades Volcano Observatory (CVO). The widely felt M 4.5 event was located ~4.5 km S of the summit (figure 3) at a depth of 6 km. Hundreds of aftershocks followed, including two greater than M 3. Typically, several earthquake swarms occur each year at Mount Hood.

Figure 3. A map of all earthquakes (M 1.0) that occurred at Hood from the start of 2001 to 29 June 2002. The area shown details a few kilometers around the M 4.5 event on 29 June 2002. Courtesy PNSN.

Information Contacts: Cascades Volcano Observatory (CVO), United States Geological Survey (USGS), 5400 MacArthur Blvd., Vancouver, WA 98661, USA (URL: http://vulcan.wr.usgs.gov/); Pacific Northwest Seismograph Network (PNSN), University of Washington, Department of Earth and Space Sciences, Box 351310, Seattle, WA 98195-1310, USA (URL: http://www.ess.washington.edu/SEIS/PNSN/).
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Mount Hood, Oregon's highest peak, forms a prominent backdrop to the state's largest city, Portland. The eroded summit area of Mount Hood consists of several andesitic or dacitic lava domes. Major Pleistocene edifice collapse produced a debris avalanche and lahar that traveled north down the Hood River valley and crossed the Columbia River. The glacially eroded volcano has had at least three major eruptive periods during the past 15,000 years. The last two occurred within the past 1800 years from the central vent high on the SW flank and produced deposits that were distributed primarily to the south and west along the Sandy and Zigzag rivers. The last major eruptive period took place beginning in 1781, when growth of the Crater Rock lava dome was accompanied by pyroclastic flows and lahars down the White and Sandy rivers. The Sandy River lahar deposits extended to the west as far as the Columbia River and were observed by members of the 1804-1805 Lewis and Clark expedition shortly after their emplacement. Minor 19th-century eruptions were witnessed from Portland.

Summary of Holocene eruption dates and Volcanic Explosivity Indices (VEI).

Start Date Stop Date Eruption Certainty VEI Evidence Activity Area or Unit
[ 1907 Aug 28 ] [ Unknown ] Uncertain     Crater Rock
[ 1869 ] [ Unknown ] Uncertain    
1865 Sep 21 1866 Jan (?) Confirmed 2 Historical Observations
1859 Aug 15 1859 Aug 17 Confirmed 2 Historical Observations
[ 1854 Aug ] [ Unknown ] Uncertain    
[ 1853 ] [ Unknown ] Uncertain    
1781 Oct 15 ± 45 days 1801 (?) Confirmed   Dendrochronology Crater Rock
0480 ± 37 years Unknown Confirmed   Radiocarbon (corrected) Crater Rock
4940 BCE ± 150 years Unknown Confirmed 2 Radiocarbon (uncorrected) Lower NE flank (SSW of Parkdale)

This compilation of synonyms and subsidiary features may not be comprehensive. Features are organized into four major categories: Cones, Craters, Domes, and Thermal Features. Synonyms of features appear indented below the primary name. In some cases additional feature type, elevation, or location details are provided.


Synonyms

Wyeast

Cones

Feature Name Feature Type Elevation Latitude Longitude
Pinnacle, the Vent 1593 m 45° 26' 0" N 121° 42' 0" W

Domes

Feature Name Feature Type Elevation Latitude Longitude
Crater Rock Dome 3219 m 45° 22' 0" N 121° 42' 0" W
Mount Hood, seen here from the north across the Columbia River Gorge, rises dramatically above low hills of older volcanic rocks. Located only 75 km ENE of Portland, Mount Hood is a popular recreation mecca for backpackers, climbers, skiers, and others who appreciate one of the scenic highlights of the Oregon Cascades.

Photo by U.S. Geological Survey, 1983.
Mount Hood, seen here from Larch Mountain on the NW side, is Oregon's most recently active volcano. A major eruptive period occurred 170-220 years ago, and 19th-century Pacific Northwest Indians and settlers observed minor eruptions.

Photo by Lee Siebert, 1980 (Smithsonian Institution).
Sharp-topped Mount Hood, Oregon's highest peak, rises above the Lolo Pass area on its NW side. Hood is a prominent landmark on both sides of the Columbia River. The summit of the glacially eroded volcano contains several lava domes. At least four major eruptive periods have occurred during the past 15,000 years, the last of which was only about 170-220 years ago. Minor 19th century eruptions were witnessed from Oregon's largest city, Portland.

Photo by Richard Fiske (Smithsonian Institution).
The upper Sandy River valley on the SW side of Mount Hood has been one of the primary channels for lahars associated with eruptions during the past 1800 years. These late-stage eruptions originated from vents high on the SW flank of the volcano.

Photo by Willie Scott, 1995 (U.S. Geological Survey).
This aerial view of Mount Hood from the south shows the Crater Rock lava dome in the center of the photo. Formation of the 400-m-wide, 170-m high Crater Rock dome is dated at about 1765 AD from tree-ring counts of wood in mudflows associated with growth of the dome. Episodic dome growth and associated pyroclastic flows and lahars took place until about 1800 AD.

Photo by Willie Scott, 1990 (U.S. Geological Survey).
Trillum Lake provides a dramatic view of the broad debris fan on the south flank of Mount Hood that originated from growth of the Crater Rock lava dome, visible on the upper SW flank just below the summit. Debris shed off the growing lava dome during the late 18th century formed the undissected fan, which provides year-round skiing from the Timberline ski area.

Photo by Dave Wieprecht, 1993 (U.S. Geological Survey).
Oregon's highest peak, Mount Hood, rises to 3426 m. This view from Frog Butte on the SE side shows the canyons of the White River in the center, and the smooth debris fan to its left that formed during of growth of the Crater Rock lava dome just south of the summit. Illumination Rock forms the knob midway up the left skyline.

Photo by Dave Wieprecht, 1993 (U.S. Geological Survey).
This aerial view from the NE shows Eliot Glacier descending the steep-walled valley at the center, with prominent glacial moraines at its base. During the late Pleistocene a major lahar from Mount Hood swept to the north across the Columbia River, temporarily filling it to a depth of 30 m.

Photo by Richard Waitt, 1983 (U.S. Geological Survey).
The north flank of Mount Hood is cut by the Eliot Glacier, with a series of prominent glacial moraines at its base. During the past 1800 years eruptions of Mount Hood have been restricted to vents on the SW flank, resulting in proportionately more erosional dissection of the north flank of the volcano.

Photo by Willie Scott, 1987 (U.S. Geological Survey).
Oregon's Mount Hood is one of the most frequently climbed volcanoes in the Cascade Range. A group of climbers above the base of Crater Rock lava dome on the upper SW flank approaches the ice-draped Steel Cliffs, which form the summit ridge.

Photo by Lee Siebert, 1968 (Smithsonian Institution).
Scientists from the U.S. Geological Survey take gas samples at Devils Kitchen near the Crater Rock lava dome on the upper SW flank of Mount Hood. The Crater Rock area is the largest fumarole field in the Oregon Cascades, producing vigorous gas emission and extensive hydrothermal alteration of rock masses over broad areas.

Photo by Bill Chadwick, 1982 (U.S. Geological Survey).
A massive volcanic mudflow produced by collapse of Mount Hood during the Pleistocene swept down the Hood River valley and traveled across the Columbia River, temporarily damming it to a depth of 30 m. This thick outcrop of the mudflow deposit, containing rounded boulders in a clay-rich matrix, is located north of Underwood, Washington, on the other side of the Columbia River.

Photo by Willie Scott, 1994 (U.S. Geological Survey).
The flat-bottomed, forested floor of the upper Sandy River is underlain by volcanic mudflow deposits associated with growth of the Crater Rock lava dome on the upper SW flank of Mount Hood. Tree-ring dating places the age of these deposits during the mid-1790's. The lahars traveled as far as the Columbia River, and the shallow, sediment-choked lower Sandy River was observed shortly after emplacement of the lahars by the Lewis and Clark expedition.

Photo by Richard Fiske, 1959 (Smithsonian Institution).
The blocky Parkdale lava flow, which traveled 6 km from a cinder cone located along the Middle Fork Hood River near the north flank of Mount Hood, towers above houses in the agricultural Hood River valley. The Parkdale flow has been radiocarbon dated at about 6890 years.

Photo by Lee Siebert, 1995 (Smithsonian Institution).

The following references have all been used during the compilation of data for this volcano, it is not a comprehensive bibliography. Discussion of another volcano or eruption (sometimes far from the one that is the subject of the manuscript) may produce a citation that is not at all apparent from the title.

Cameron K A, Pringle P T, 1987. A detailed chronology of the most recent major eruptive period at Mount Hood, Oregon. Geol Soc Amer Bull, 99: 845-851.

Cameron K A, Pringle P T, 1991. Prehistoric buried forests of Mount Hood. Oregon Geol, 53: 34-43.

Crandell D R, 1980. Recent eruptive history of Mount Hood, Oregon, and potential hazards from future eruptions. U S Geol Surv Bull, 1492: 1-81.

Cribb J W, Barton M, 1997. Significance of crustal and source region processes on the evolution of compositionally similar calc-alkaline lavas, Mt. Hood, Oregon. J Volc Geotherm Res, 76: 229-249.

Harris S L, 1988. Fire Mountains of the West: the Cascade and Mono Lake Volcanoes. Missoula, MT: Mountain Press, 379 p.

Hildreth W E, 2007. Quaternary magmatism in the Cascades--geologic perpectives. U S Geol Surv Prof Pap, 1744: 1-125.

IAVCEI, 1973-80. Post-Miocene Volcanoes of the World. IAVCEI Data Sheets, Rome: Internatl Assoc Volc Chemistry Earth's Interior..

Katsui Y (ed), 1971. List of the World Active Volcanoes. Volc Soc Japan draft ms, (limited circulation), 160 p.

Pierson T C, Pringle P T, Cameron K A, 2011. Magnitude and timing of downstream channel aggradation and degradation in response to a dome-building eruption at Mount Hood, Oregon. Geol Soc Amer Bull, 123: 3-20.

Pringle P T, Pierson T C, Cameron K A, Sheppard P R, 2010. Late Eighteenth century Old Maid eruption and lahars at Mount Hood, Oregon (USA) dated with tree rings and historical observations. In: Stoffel M, Bollschweiler M, Butler D R, Luckman B H (eds), {Tree Rings and Natural Hazards: A State-of-the-Art}. Berlin: Springer-Verlag, p 487-491.

Sherrod D R, Smith J G, 1990. Quaternary extrusion rates of the Cascade Range, northwestern United States and southern British Columbia. J Geophys Res, 95: 19,465-19,474.

Wise W S, 1969. Geology and petrology of the Mount Hood area: a study of High Cascades volcanism. Geol Soc Amer Bull, 80: 969-1006.

Wise W S, 1968. Geology of the Mount Hood volcano. Oregon Dept Geol Min Ind Bull, 62: 81-98.

Wood C A, Kienle J (eds), 1990. Volcanoes of North America. Cambridge, England: Cambridge Univ Press, 354 p.

Volcano Types

Stratovolcano
Lava dome(s)
Pyroclastic cone

Tectonic Setting

Subduction zone
Continental crust (> 25 km)

Rock Types

Major
Andesite / Basaltic Andesite
Minor
Dacite

Population

Within 5 km
Within 10 km
Within 30 km
Within 100 km
0
850
9,721
2,067,520

Affiliated Databases

Large Eruptions of Hood Information about large Quaternary eruptions (VEI >= 4) is cataloged in the Large Magnitude Explosive Volcanic Eruptions (LaMEVE) database of the Volcano Global Risk Identification and Analysis Project (VOGRIPA).
WOVOdat WOVOdat is a database of volcanic unrest; instrumentally and visually recorded changes in seismicity, ground deformation, gas emission, and other parameters from their normal baselines. It is sponsored by the World Organization of Volcano Observatories (WOVO) and presently hosted at the Earth Observatory of Singapore.
EarthChem EarthChem develops and maintains databases, software, and services that support the preservation, discovery, access and analysis of geochemical data, and facilitate their integration with the broad array of other available earth science parameters. EarthChem is operated by a joint team of disciplinary scientists, data scientists, data managers and information technology developers who are part of the NSF-funded data facility Integrated Earth Data Applications (IEDA). IEDA is a collaborative effort of EarthChem and the Marine Geoscience Data System (MGDS).
Smithsonian Collections Search the Smithsonian's NMNH Department of Mineral Sciences collections database. Go to the "Search Rocks and Ores" tab and use the Volcano Name drop-down to find samples.